We need to listen to the surgeons who ignore AF in their cardiac surgery patients to understand how to improve the situation. According to a survey on barriers to adoption of concomitant AF ablation, almost 90% of surgeons are aware of the guidelines, so there is little room for improvement there. However, only about half of the surgeons learned how and when to perform AF surgical ablation in residency or fellowship or took specialized courses devoted to the surgical ablation of AF. More support from the Thoracic Surgery Directors Association for the inclusion of AF surgery in the training curriculum and more aggressive requirements for AF surgical experience during training by the Thoracic Surgery Residency Review Committee and the American Board of Thoracic Surgery are needed. Improved residency training may require outside visiting surgeon lectures, demonstrations, simulations, and videos to educate the trainees on the “basics” of AF and AF surgery, the benefits of concomitant AF surgery, and the appropriate ablation procedure for an individual patient with AF who requires CABG, valve, or thoracic aortic surgery. Ideally, the visits would be in person, but virtual conferences and prerecorded videos may be a good start for learning the basics.

We also need to address the biggest issue, which is that surgeons believe that the operation is too complex and dangerously increases aortic cross-clamp time. Reports indicate they may be correct, especially if a full Cox-Maze-III or IV procedure is the operation called for in a specific patient and the surgeon has little or no experience with AF surgical ablation (see Chapters 15 and 25 ). However, numerous studies have consistently documented that in experienced and properly trained hands, the addition of a Maze procedure to CABG and/or valve surgery does not adversely affect the surgical morbidity or mortality rates. ^, Indeed, Badhwar et al. reported a large STS database analysis showing that the addition of AF ablation to MVR, CABG, aortic valve replacement (AVR), or CABG plus AVR procedures actually decreased the 30-day operative mortality rate. Both the STS guidelines and the American Association for Thoracic Surgery (AATS) Expert Opinion Consensus confirmed that concomitant AF surgery did not impact operative morbidity and that it either decreased or had no impact on operative mortality rates. Thus, both of these thoracic surgery societies strongly support the addition of concomitant AF ablation to these index surgical procedures and they should have eliminated any safety concern about adding a concomitant Maze procedure in patients with AF undergoing the most common types of cardiac surgery. Of course, the surgical procedures in all of these studies were done by experienced surgeons, again emphasizing the need for improved training in AF ablation techniques.

In the survey, surgeons were also concerned about postoperative arrhythmias and the need for new pacemakers. Therefore, they assumed that patient risk was automatically increased by adding a concomitant AF ablation procedure. We can point to the STS data showing reduced 30-day mortality and stroke rates, but with only 50% of surgeons trained in surgical ablation or who took courses, would that still be true if suddenly large numbers of surgeons were trying to add a full Cox Maze-III or Cox Maze-IV to all operations? Seems unlikely. To keep the 30-day, publicly reported, risk at a low level (trying to get three stars from STS!) many surgeons have opted to just skip the ablation. To reverse this unfortunate practice, we need a change in mindset to a more practical approach and hopefully, new technology.

“The enemy of good is better” (Voltaire; attributed). For years we have preached to surgeons that a full Cox Maze-III or Cox Maze-IV procedure using cryoablation and/or bipolar radiofrequency (RF) is the “best” way to treat patients with concomitant AF, and it is. Some would add it’s the “only” way to treat patients with AF. But the non-arrhythmia surgeons are right. It does add aortic cross-clamp time, and in their hands, it could increase the 30-day operative mortality risk. Maybe “less is more” (fewer lesions but more ablation in this case) (Ludwig Mies van der Rohe; attributed). Left atrial ablation alone is acceptable for mitral operations without right-sided involvement in reoperations (see Chapters 25 and 27 ), and pulmonary vein (PV) isolation alone is a good choice for a recent graduate doing a low ejection fraction CABG with paroxysmal AF on the weekend with no senior partner nearby, an epicardial box lesion with a clamp and left atrial appendage (LAA) closure may be a good choice with surgical aortic valve replacement for an aortic stenosis patient with paroxysmal AF compared with transcatheter aortic valve replacement alone. The options for treatment need to be expanded. A Cox Maze-III or Cox Maze-IV procedure performed by an experienced surgeon is certainly a good option for most patients in most situations, but it should not be considered the only option for all patients.

LAA closure, with complete occlusion and a residual stump of less than 10 mm, is safe, fast, durable, and easy. All surgeons, even new graduates, can do this procedure, especially with the AtriClip. Although suture closure is certainly less expensive than device closure, it has been associated with incomplete occlusion and has some risk of bleeding when the LAA is excised. However, this may be the preferred approach in certain situations, such as in a reoperation mitral valve (MV) procedure (see Chapter 15 ). There are many commercially available LAA closure devices in various sizes and shapes, and no doubt more are coming in the future. The Left Atrial Appendage Occlusion Study (LAAOS) III trial clearly demonstrated the benefit of adding LAAO, and a variety of types of occlusion were used in that trial. LAAO should be considered, whenever possible, in every patient with preexisting AF unless there is a specific contraindication to closing the LAA.

An effective way to change surgeon behavior would be to add LAAO as a quality metric, similar to the situation with LIMA–LAD for coronary artery bypass. This seems like a simple step, but there is only one procedure relating to coronary artery bypass, LIMA–LAD, that is a quality metric. Considering that LAAO is simple, safe, and effective, it should be adopted as standard operating procedure. Studies demonstrated low uptake in California (51% in 2019), but this may be “old news” because it increased every year from 2016 through 2019. In Michigan, a concerted effort to increase compliance was put in place, and reported compliance reached 79% at the end of the study. There will need to be exceptions (there are also a few for the use of LIMA–LAD), and reoperations will be the most common exception. Others could include pericardial adhesions, poor tissue quality with a significant risk for bleeding in the judgement of the surgeon, and anatomy unfavorable for LAA closure (rare). Despite these caveats, concomitant LAAO for patients with AF should approach 100% utilization, as does LIMA–LAD grafting in coronary patients.

In view of the universally recognized positive impact of concomitant AF surgical ablation (SA) on postoperative stroke rates and long-term survival, concomitant SA clearly should be performed far more often than it is currently (<25%). Discussion continues to revolve around the best technology, the preferred lesion set (biatrial Maze, LA Maze, PVI, CTI, etc), and which patients should have concomitant AF ablation. Even though there is still no consensus on these issues, any of the SA procedures is preferable to ignoring the AF completely (>75%). Thus, while it would be inappropriate to declare a specific lesion pattern (say, a biatrial Maze procedure) as a quality metric, the designation of the general category of “concomitant AF surgical ablation,” which would include any of the lesions sets, should be strongly encouraged as a part of every cardiac surgical procedure in a patient with preoperative AF. The surgical societies and guideline committees that mandate near 100% adoption of concomitant SA of AF are responding to the accumulation of a vast body of positive evidence in making their recommendations, and they are on firm ground in doing so with or without declaring it to be a quality metric.

As of this writing, there are no published clinical data using the latest surgical ablation technology, the EnCompass Bipolar Radiofrequency Clamp (AtriCure, Inc., Mason, OH), which was specifically designed for operations such as CABG and AVR in which the left atrium is not normally opened. Using this new clamp in CABG or AVR patients creates a box lesion with one tissue clamping, and the results in animal studies have been favorable. However currently, the entire electrophysiology community is enamored with pulsed-field ablation (PFA), and this new clamp will likely be adapted to currently available RF and cryosurgical devices in the next few years. Surgical devices using PFA instead of bipolar RF have the potential to be much faster, which will be a welcome improvement, but as discussed in Chapter 52 , initial reports on the efficacy of PFA compared with RF and cryosurgery are disappointing. Ultra-low-temperature cryoablation (ULTC) cryocatheters using “near-critical nitrogen,” which is essentially liquid nitrogen suspended in a gaseous state at–196°C, have met with initial clinical success for the ablation of atrial flutter, AF, and ventricular tachycardia. We expect that this promising new technology will be adapted to surgical devices in the future. Experimental studies with catheters that combine ULTC and PFA (called PFCA) have been promising, but no clinical data on PFCA ablation are currently available. These new single and combined ablation energy sources are discussed in more detail in Chapter 52 . Although they are currently being developed for treating patients with stand-alone AF and ventricular tachycardia with catheters, they will undoubtedly be adapted in the future for use in surgical devices as well. Similarly, LAA closure devices ideally will be easier to apply in minimally invasive and robotic procedures in the future.

When surgeons are operating on patients for other reasons, it is a simple procedure to close the LAA, and the potential danger of an open LAA has been recognized for many years. Meta-analyses, single-center studies, and database studies have demonstrated a reduced risk of stroke in patients with no history of AF who undergo LAAO versus those without LAAO. ^, This makes sense intuitively, particularly in patients with a significant underlying risk of developing AF and therefore stroke. Such patients may be older, have a CHA _₂ DS _₂ -VASc score of 3 or more, have a dilated atrium, or have other markers of “atrial myopathy.” The ongoing 6,000-patient randomized clinical LEft Atrial Appendage Exclusion for Prophylactic Stroke reduction (LeAAPS) trial will shed light on this subject. Assuming that this trial is positive and shows that LAAO-treated patients with no history of AF have a lower long-term risk of stroke, it will set the stage for another important question: “Can anticoagulation be withheld in patients with successful LAAO if they develop AF?”.

A riskier trial would be to study concomitant surgical ablation to prevent new-onset postoperative AF and/or late recurrent AF. However, the trigger mechanisms for new-onset postoperative AF (POAF) are not the same as the PV triggers that induce typical AF (see Chapter 47 ), so prophylactic surgical ablation for AF may not have a significant early impact on new-onset POAF. We do know that Maze surgery does not prevent POAF, but we do not know whether or not the early POAF after a Maze procedure is similar to new-onset POAF in a patient with no preoperative history of AF. However, a reduction in late recurrent AF could be reasonably expected after such a prophylactic surgical ablation depending on the patient population. A patient population with no history of AF but with a high risk for developing AF in the future would be an interesting trial target, but even MV patients with no AF history had only a 22% rate of developing de novo AF on 10-year follow-up, so such a trial design may be impractical. These trials have been discussed for many years, but with the success of LAAOS III, there is growing interest in large surgical randomized controlled trials in AF therapy.